Transmitting uplink control information over a data channel or over a control channel

ABSTRACT

Methods and apparatus are described for a User Equipment (UE) to concurrently transmit Uplink Control Information (UCI) and data information to a Node B. The Node B can configure the UE whether to transmit UCI together with data information in a Physical Uplink Shared CHannel (PUSCH) or, separate from data information, in a Physical Uplink Control CHannel (PUCCH). The UE may also determine whether to transmit UCI together with data information in the PUSCH or, separate from data information, in the PUCCH based on criteria involving either a ratio of PUSCH resources for UCI transmission over the total PUSCH resources, a Modulation and Coding Scheme (MCS) for the data information, an absolute power difference between PUCCH and PUSCH transmissions, whether the PUSCH transmission uses frequency hopping, or whether spatial multiplexing is used for the data transmission.

PRIORITY

The present application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 61/148,653, entitled “Transmitting UplinkControl Information over a Data Channel or over a Control Channel”,which was filed on Jan. 30, 2009, the content of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to wireless communication systems and,more particularly, to the transmission of control information in theuplink of a communication system.

2. Description of the Art

A communication system consists of a DownLink (DL), supportingtransmissions of signals from a base station (Node B) to User Equipments(UEs), and of an UpLink (UL), supporting transmissions of signals fromUEs to the Node B. A UE, also commonly referred to as a terminal or amobile station, may be fixed or mobile and may be a wireless device, acellular phone, a personal computer device, etc. A Node B is generally afixed station and may also be referred to as a Base Transceiver System(BTS), an access point, or some other terminology.

UL signals consist of data signals, carrying the information content,control signals, and Reference Signals (RS), which are also known aspilot signals. The UEs convey UL data signals through a Physical UplinkShared CHannel (PUSCH). The UL control signals include acknowledgementsignals associated with the application of Hybrid Automatic RepeatreQuest (HARM), Service Request (SR) signals, Channel Quality Indicator(CQI) signals, Precoding Matrix Indicator (PMI) signals, or RankIndicator (RI) signals. Any combination of HARQ-ACKnowledgement(HARQ-ACK), SR, CQI, PMI, or RI will be referred to as Uplink ControlInformation (UCI). UCI can be transmitted in a Physical Uplink ControlCHannel (PUCCH) or, together with data, in the PUSCH over a TransmissionTime Interval (TTI).

A UE transmits an HARQ-ACK signal in response to data packet receptionin the DL. Depending on whether the data packet reception is correct orincorrect, the HARQ-ACK signal has an ACK or a NAK value, respectively.The UE transmits an SR signal to request UL resources for signaltransmission. The UE transmits a CQI signal to inform the Node B of theDL channel conditions it experiences, enabling the Node B to performchannel-dependent scheduling of DL data packets. The UE transmits PMI/RIsignals to inform the Node B how to combine the transmission of a signalto the UE from multiple Node B antennas in accordance with aMultiple-Input Multiple-Output (MIMO) principle. Any of the possiblecombinations of HARQ-ACK, SR, CQI, PMI, and RI signals may betransmitted by a UE jointly with data information in the PUSCH, orseparate from data information in the PUCCH.

A structure for the PUSCH transmission in the UL TTI, which forsimplicity is assumed to consist of one sub-frame, is illustrated inFIG. 1. A sub-frame 110 includes two slots. Each slot 120 includesN_(symb) ^(UL) symbols used for the transmission of data information,UCI, or RSs. Each symbol 130 further includes a Cyclic Prefix (CP) tomitigate interference due to channel propagation effects. The PUSCHtransmission in one slot may be in the same or a different part of theoperating BandWidth (BW) as/than the PUSCH transmission in the otherslot. Some symbols in each slot can be used for RS transmission 140 toprovide channel estimation and to enable coherent demodulation of thereceived signal. The transmission BW is assumed to consist of frequencyresource units, which will be referred to as Physical Resource Blocks(PRBs). Each PRB is further assumed to consist of N_(sc) ^(RB)sub-carriers, or Resource Elements (REs). A UE is allocated M_(PUSCH)PRBs 150 for PUSCH transmission for a total of M_(sc)^(PUSCH)=M_(PUSCH)·N_(sc) ^(RB) REs for the PUSCH transmission BW. Thelast symbol of a sub-frame may be used for the transmission of aSounding Reference Signal (SRS) 160, from one or more UEs, whose primarypurpose is to provide a CQI for the UL channel that each of these UEsexperiences.

A UE transmitter block diagram for UCI and data transmission in the samePUSCH sub-frame is illustrated in FIG. 2. Coded CQI bits and/or PMI bits205 and coded data bits 210 are multiplexed in step 220. If HARQ-ACKbits also need to be multiplexed, data bits are punctured to accommodateHARQ-ACK bits in step 230. A Discrete Fourier Transform (DFT) of thecombined data bits and UCI bits is then obtained in step 240. The REscorresponding to the assigned transmission BW are selected viasub-carrier mapping in step 250 through the control of localized FDMA instep 255. The Inverse Fast Fourier Transform (IFFT) is performed in step260. The CP is inserted in step 270 and filtering is applied via timewindowing in step 280 to achieve a transmitted signal 290. Additionaltransmitter circuitry such as a digital-to-analog converter, analogfilters, amplifiers, and transmitter antennas are not illustrated. Also,the encoding process for the data bits and the CQI and/or PMI bits, aswell as the modulation process for all transmitted bits, are omitted forbrevity. The PUSCH signal transmission is assumed to be over clusters ofcontiguous REs in accordance to the DFT Spread Orthogonal FrequencyMultiple Access (DFT-S-OFDMA) method allowing signal transmission overone cluster 295A (also known as Single-Carrier Frequency DivisionMultiple Access (SC-FDMA)), or over multiple non-contiguous clusters ofcontiguous BW 295B.

The Node B receiver performs the reverse (complementary) operations ofthose of the UE transmitter. This is conceptually illustrated in FIG. 3where the reverse operations of those illustrated in FIG. 2 areperformed. After an antenna receives the Radio-Frequency (RF) analogsignal and after further processing units (such as filters, amplifiers,frequency down-converters, and analog-to-digital converters) which arenot shown for brevity, a digital signal 310 is filtered via timewindowing in step 320 and the CP is removed in step 330. Subsequently,the Node B receiver applies a Fast Fourier Transform (FFT) in step 340.The REs used by the UE transmitter are selected via sub-carrierdemapping in step 350 under the control of reception bandwidth in step345. An Inverse DFT (IDFT) is applied in step 360. The HARQ-ACK bits areextracted and respective erasures for the data bits are placed in step370. Data bits 390 and CQI/PMI bits 395 are de-multiplexed in step 380.Well known Node B receiver functionalities such as channel estimation,demodulation, and decoding are not shown for brevity.

A structure for the PUCCH transmission in one slot of a sub-frame isillustrated in FIG. 4 for HARQ-ACK, SR, or RI transmission, and in FIG.5 for CQI or PMI transmission. The transmission in the other slot, whichmay be at a different part of the operating BW for frequency diversity,has the same structure with the possible exception of the last symbol,which may be punctured to accommodate SRS transmission for the PUSCH.The PUCCH transmission for each UCI signal is assumed to be in one PRB.

Referring to FIG. 4, a HARQ-ACK (or SR, or RI) transmission structure410 includes the transmission of HARQ-ACK signals and RS for enablingcoherent demodulation of the HARQ-ACK signals. HARQ-ACK bits 420modulate 430 a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence440, for example with BPSK or QPSK modulation, which is then transmittedafter performing the IFFT operation, as is subsequently described. EachRS 450 is transmitted through the non-modulated CAZAC sequence.

Referring to FIG. 5, CQI (or PMI) transmission structure 510 includesthe transmission of CQI signals and RS. CQI bits 520 again modulate 530a CAZAC sequence 540, for example using QPSK modulation, which is thentransmitted after performing the IFFT operation. Each RS 550 istransmitted through the non-modulated CAZAC sequence.

An example of CAZAC sequences is given by Equation (1) below.

$\begin{matrix}{{c_{k}(n)} = {\exp\left\lbrack {\frac{j\; 2\pi\; k}{L}\left( {n + {n\frac{n + 1}{2}}} \right)} \right\rbrack}} & (1)\end{matrix}$where L is the length of the CAZAC sequence, n is the index of anelement of the sequence n={0, 1, . . . , L−1}, and k is the index of thesequence. If L is a prime integer, there are L−1 distinct sequenceswhich are defined as k ranges in {0, 1, . . . , L−1}. If the PRBsconsist of an even number of REs, such as for example N_(sc) ^(RB)=12,CAZAC sequences with even length can be directly generated throughcomputer search for sequences satisfying the CAZAC properties.

FIG. 6 is a diagram illustrating a UE transmitter structure for a CAZACsequence that can be used non-modulated as an RS or modulated as anHARQ-ACK signal or CQI signal using BPSK (1 HARQ-ACK bit) or QPSK (2HARQ-ACK bits or CQI bits). The frequency-domain version of a computergenerated CAZAC sequence is used in step 610. The REs corresponding tothe assigned PUCCH BW are selected via sub-carrier mapping in step 630under control of the transmission bandwidth in step 620. An IFFT isperformed in step 640, and a CS is applied to the output in step 650 asis subsequently described. The CP is inserted in step 660 and filteringvia time windowing is applied in step 670 resulting in transmittedsignal 680. Zero padding is assumed to be inserted by the reference UEin REs used for the signal transmission by other UEs and in guard REs(not shown). Moreover, for brevity, additional transmitter circuitrysuch as digital-to-analog converter, analog filters, amplifiers, andtransmitter antennas as they are known in the art, are not shown.

The reverse (complementary) transmitter functions are performed at theNode B receiver for the reception of the CAZAC sequence. This isconceptually illustrated in FIG. 7 where the reverse operations of thosein FIG. 6 apply. An antenna receives RF analog signal and after furtherprocessing units (such as filters, amplifiers, frequencydown-converters, and analog-to-digital converters) a digital receivedsignal 710 is filtered via time windowing in step 720 and the CP isremoved in step 730. Subsequently, the CS is restored in step 740, anFFT is applied in step 750. The transmitted REs are selected in step 760via sub-carrier demapping under control of reception bandwidth in step765. FIG. 7 also shows the subsequent correlation with the replica ofthe CAZAC sequence in step 780 by multiplier in step 770. Finally,output 790 is obtained which can then be passed to a channel estimationunit, such as a time-frequency interpolator, for an RS, or can to detectthe transmitted information, for the CAZAC sequence modulated byHARQ-ACK information bits or CQI information bits.

Different CSs of the same CAZAC sequence provide orthogonal CAZACsequences. Therefore, different CSs of the same CAZAC sequence can beallocated to different UEs in the same PRB for their RS, or UCI signaltransmission and achieve orthogonal UE multiplexing. This principle isillustrated in FIG. 8. In order for multiple CAZAC sequences 810, 830,850, 870, respectively generated from multiple CSs 820, 840, 860, 880 ofthe same CAZAC sequence to be orthogonal, CS value Δ890 should exceedthe channel propagation delay spread D (including a time uncertaintyerror and filter spillover effects). If T_(s) is the DFT-S-OFDM symbolduration, the number of such CSs is equal to the mathematical floor ofthe ratio T_(s)/D.

Orthogonal multiplexing for the HARQ-ACK PUCCH transmission structurecan be achieved not only through different CS values of the CAZACsequence, but also by applying orthogonal covering in the time domain.The HARQ-ACK and RS symbols in each slot are respectively multipliedwith a first and a second orthogonal code. However, these multiplexingaspects are not material to the invention and further description isomitted for brevity.

When UCI is transmitted in the PUSCH, some REs that would otherwise beused for data are used for UCI, which usually requires better receptionreliability than data. As a result more REs are required to transmit aUCI bit than a data bit. Additionally, UCI may require differentreception reliability depending on their type. For example, the targetBit Error Rate (BER) for HARQ-ACK is typically much lower than that ofCQI/PMI, since erroneous reception of HARQ-ACK has more detrimentalconsequences and, due their small number, HARQ-ACK bits are protectedthrough repetition coding while more powerful coding methods can applyto CQI/PMI bits. The number of REs required for UCI transmission in thePUSCH is proportional to the spectral efficiency of the datatransmission as determined by the data Modulation and Coding Scheme(MCS). For a certain target data BLock Error Rate (BLER), the MCSdepends on the Signal to Interference and Noise Ratio (SINR) the ULsignal transmission experiences. As the Node B scheduler may vary thetarget data BLER, it may configure an offset for the number of REs ofeach UCI signal in order to avoid having only an exclusive link with thedata MCS.

Among the UCI signals, HARQ-ACK signals have the highest reliabilityrequirements and the respective REs are located next to the RS in eachslot in order to obtain the most accurate channel estimate for theirdemodulation. The number of coded symbols Q′ for the HARQ-ACK (or RI)transmission in the PUSCH can be determined as set forth in Equation(2).

$\begin{matrix}{Q^{\prime} = {\min\left( {\left\lceil \frac{O \cdot \beta_{offset}^{{ACK}/{NAK}}}{Q_{m} \cdot R} \right\rceil,{4 \cdot M_{sc}^{{PUSCH} - {current}}}} \right)}} & (2)\end{matrix}$where O is the number of HARQ-ACK (or RI) bits (for example, 1 or 2),β_(offset) ^(ACK/NAK) is the offset configured to the UE by the Node B,and M_(sc) ^(PUSCH-current) is the PUSCH BW in the current sub-frame.Q_(m) and R are respectively the number of bits for data modulation(Q_(m)=2, 4, 6 for QPSK, QAM16, QAM64, respectively) and the data coderate of the initial PUSCH transmission for the same transport block. Thelink between HARQ-ACK REs and data MCS is through Q_(m)·R. The code rateR is defined as

$R = {\left( {\sum\limits_{r = 0}^{C - 1}K_{r}} \right)/\left( {Q_{m} \cdot M_{sc}^{PUSCH} \cdot N_{symb}^{PUSCH}} \right)}$where N_(symb) ^(PUSCH)=(2·(N_(symb) ^(UL)1)−N_(SRS)) with N_(SRS)=1 ifSRS transmission at least partially overlaps with the PUSCH BW andN_(SRS)=0 otherwise. Finally, C is the total number of code blocks andK_(r) is the number of bits for code block number r. The number ofHARQ-ACK (or RI) REs is limited to the ones corresponding to 4DFT-S-OFDM symbols per sub-frame (2 symbols per slot). A similarexpression applies for the number of coded CQI/PMI symbols per sub-framewhich is omitted for brevity. The principle of the linkage of the UCIresources to the data MCS and the assigned UCI offset is described abovefor the HARQ-ACK (or RI) symbols.

There are several reasons for UCI to be in the PUSCH, when it occurswith data in the same sub-frame, and not in the PUCCH. A first reason isthat concurrent transmission of data in the PUSCH and UCI in the PUCCHincreases the Peak-to-Average Power Ratio (PAPR) or the Cubic Metric(CM) of the combined signal transmission, which then requires highertransmission power in both PUCCH and PUSCH to achieve the same receptionreliability as when only one of the PUSCH or PUCCH is transmitted. Thisincrease in power increases interference and may not even be possiblefor power limited UEs. A second reason is the UCI payload may not bepossible to transmit in the PUCCH. For example, for the CQI transmissionstructure in FIG. 5, only 20 coded CQI symbols can be transmitted persub-frame and therefore, detailed CQI reports need to be sent throughthe PUSCH.

While UCI and data transmission in the PUSCH preserves thesingle-carrier property and avoids increasing the CM of PUSCHtransmission, it is not spectrally efficient as PUCCH resources assignedto UCI transmission remain unused. Also, multiplexing UCI in the PUSCHmay often result in an excessive number of REs being used for UCIinstead of data.

In addition to concurrent transmission of UCI and data, concurrenttransmission of various UCI signals may often occur. For example,HARQ-ACK and CQI transmission may need to occur in the same sub-frame inthe absence of data transmission from a UE. To preserve thesingle-carrier property and avoid increasing the CM of concurrenttransmissions of HARQ-ACK and CQI signals, multiplexing of the two canbe in the same PUCCH. For example, HARQ-ACK transmission can bemultiplexed in the PUCCH structure of FIG. 5, which is used for CQItransmission by scaling the second RS in each slot by “−1” if ACK istransmitted, and by “+1” if NAK is transmitted, as is the case in 3^(rd)Generation Partnership Project (3GPP) Long Term Evolution (LTE).However, the PUCCH assigned to HARQ-ACK transmission remains unused andthe HARQ-ACK BER may degrade relative to when the HARQ-ACK signaltransmission uses its own PUCCH resources.

SUMMARY OF THE INVENTION

The present invention has been made to address at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present inventionprovides methods and apparatus for a UE to perform concurrenttransmissions to a Node B of Uplink Control Information (UCI) eitherjointly with data information in a Physical Uplink Shared CHannel(PUSCH) or separate from data information in a Physical Uplink ControlCHannel (PUCCH) during the same Transmission Time Interval (TTI).

According to one aspect of the present invention, a method is providedfor a UE of a communication system to decide whether to transmit controlinformation together with data information in a PUSCH or separate fromthe data information in a PUCCH during the same TTI. An informationelement that configures whether the UE transmits the control informationtogether with the data information in the PUSCH or separate from thedata information in the PUCCH during the same TTI, is received by theUE. The control information is transmitted by the UE together with thedata information in the PUSCH, when the information element has a firstvalue. The control information is transmitted in the PUCCH and the datainformation is transmitted in the PUSCH by the UE, when the informationelement has a second value.

According to another aspect of the present invention, a method isprovided for a UE of a communication to decide whether to transmitcontrol information together with data information in a PUSCH orseparate from the data information in a PUCCH during the same TTI. Aratio of an amount of resources required for transmission of the controlinformation in the PUSCH over a total amount of resources available fortransmission of the data information or the control information in thePUSCH is determined by the UE. The control information is transmittedtogether with the data information in the PUSCH by the UE, when theratio is less than or equal to a threshold value. The controlinformation is transmitted in the PUCCH and the data information istransmitted in the PUSCH, when the ratio is greater than the thresholdvalue.

According to an additional aspect of the present invention, a method isprovided for a UE to transmit control information together with datainformation in a PUSCH or separate from the data information in a PUCCHduring the same TTI. The control information is transmitted togetherwith the data information in the PUSCH, when a value of an MCS used forthe data information is greater than a predetermined MCS value. Thecontrol information is transmitted in the PUCCH and the data informationis transmitted in the PUSCH, when the value of the MCS used for the datainformation is less than or equal to the predetermined MCS value.

According to a further aspect of the present invention, a method isprovided for a UE to determine a transmission power of a first channeland of a second channel. The first channel is transmitted with a firstnominal transmission power and the second channel is transmitted with asecond nominal transmission power, when an absolute value of adifference between the first nominal transmission power and the secondnominal transmission power is less than or equal to a threshold value.The first channel is transmitted with the first nominal transmissionpower and transmission of the second channel is suspended, when theabsolute value of the difference between the first nominal transmissionpower and the second nominal transmission power is greater than thethreshold value.

According to another aspect of the present invention, a method isprovided for a UE to transmit control information together with datainformation in a PUSCH or separate from the data information in a PUCCHduring the same TTI. The control information is transmitted in the PUCCHand the data information is transmitted in the PUSCH, when the datatransmission uses spatial multiplexing in accordance with a MIMOtransmission method. The control information is transmitted togetherwith the data information in the PUSCH, when the data transmission doesnot use spatial multiplexing in accordance with the MIMO transmissionmethod.

Additionally, according to a further aspect of the present invention, aUE apparatus is provided for transmitting data information in a PUSCHand control information either in the PUSCH or in a PUCCH. The apparatusincludes a comparator for comparing a ratio of an amount of resourcesrequired for transmission of the control information in the PUSCH over atotal amount of resources available for transmission of the datainformation or the control information in the PUSCH to a thresholdvalue. The apparatus also includes a transmitter operating in a firstmode for transmitting the control information together with the datainformation in the PUSCH, when the ratio is less than or equal to thethreshold value. The apparatus further includes transmitter operating ina second mode for transmitting the control information in the PUCCH andthe data information in the PUSCH, when the ratio is greater than thethreshold value.

According to an aspect of the present invention, a UE apparatus isprovided for transmitting data information in a PUSCH and controlinformation either in the PUSCH or in a PUCCH. The apparatus includes atransmitter operating in a first mode for transmitting the controlinformation together with the data information in the PUSCH, when avalue of an MCS used for data transmission is greater than apredetermined MCS value. The apparatus also includes a transmitteroperating in a second mode for transmitting the control information inthe PUCCH and the data information in the PUSCH, when the value of theMCS used for the data transmission is less than or equal to thepredetermined MCS value.

According to an additional aspect of the present invention, a UEapparatus is provided for transmitting data information in a PUSCH andcontrol information either in the PUSCH or in a PUCCH. The apparatusincludes a transmitter operating in a first mode for transmitting thecontrol information in the PUCCH and the data information in the PUSCH,when data transmission uses spatial multiplexing in accordance with aMIMO transmission method. The apparatus also includes a transmitteroperating in a second mode for transmitting the control informationtogether with the data information in the PUSCH, when the datatransmission does not use spatial multiplexing in accordance with theMIMO transmission method.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinvention will be more apparent from the following detailed descriptionwhen taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a sub-frame structure for PUSCHtransmission;

FIG. 2 is a block diagram illustrating a transmitter structure for thetransmission of data information and control information in the PUSCH;

FIG. 3 is a block diagram illustrating a receiver structure for thereception of data information and control information in the PUSCH;

FIG. 4 is a block diagram illustrating a sub-frame structure forHARQ-ACK transmission in the PUCCH;

FIG. 5 is a block diagram illustrating a sub-frame structure for CQItransmission in the PUCCH;

FIG. 6 is a block diagram illustrating a transmitter structure for aCAZAC sequence;

FIG. 7 is a block diagram illustrating a receiver structure for a CAZACsequence;

FIG. 8 is a diagram illustrating a multiplexing of CAZAC sequencesthrough the application of different cyclic shifts;

FIG. 9 is a diagram illustrating the enabling or disabling of concurrentPUCCH and PUSCH transmissions from a UE through the use of an“Enable_PUCCH_PUSCH” flag configured to the UE from the Node B,according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating the comparison by the UE of the ratioof the resources for the transmission of control information in thePUSCH over the total PUSCH resources to a threshold in order todetermine whether to transmit control information together with datainformation if the PUSCH or whether to transmit control information inthe PUCCH and data information in the PUSCH during the same sub-frame,according to an embodiment of the present invention;

FIG. 11 is a diagram illustrating the comparison by the UE of theabsolute difference between the powers for transmission in the PUCCH andthe PUSCH to a threshold in order to determine whether to transmitcontrol information together with data information if the PUSCH orwhether to transmit control information in the PUCCH and datainformation in the PUSCH during the same sub-frame, according to anembodiment of the present invention;

FIG. 12 is a diagram illustrating the decision by the UE to transmitcontrol information in the PUCCH depending on whether the datatransmission in the PUSCH uses the MIMO transmission method, accordingto an embodiment of the present invention;

FIG. 13 is a diagram illustrating the enabling or disabling ofconcurrent transmissions from a UE of HARQ-ACK and CQI controlinformation in the PUCCH through the use of an “Enable_HARQ-ACK_CQI”flag configured to the UE from the Node B, according to an embodiment ofthe present invention; and

FIG. 14 is a diagram illustrating the simultaneous transmission of 2HARQ-ACK bits multiplexed in the CQI transmission structure in the PUCCHand the transmission of other HARQ-ACK bits using the HARQ-ACKtransmission structure in the PUCCH, according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Embodiments of the present invention are described in detail withreference to the accompanying drawings. The same or similar componentsmay be designated by the same or similar reference numerals althoughthey are illustrated in different drawings. Detailed descriptions ofconstructions or processes known in the art may be omitted to avoidobscuring the subject matter of the present invention.

Additionally, although the present invention is described in relation toan Orthogonal Frequency Division Multiple Access (OFDMA) communicationsystem, it also applies to all Frequency Division Multiplexing (FDM)systems in general and to SC-FDMA, Orthogonal Frequency DivisionMultiplexing (OFDM), Frequency Division Multiple Access (FDMA),DFT-spread OFDM, DFT-spread OFDMA, Single Carrier (SC)-OFDMA, andSC-OFDM in particular.

The embodiments of the present invention first consider rules fordeciding when to multiplex UCI with data in the PUSCH and when totransmit UCI and data through separate channels (PUCCH and PUSCH,respectively) in the same sub-frame.

A first embodiment of the present invention considers that the Node Binforms each UE, either through UE-specific higher layer signaling (inthe Medium Access Control (MAC) layer or in the Radio Resource Control(RRC) layer) or though signaling in the DL control channel (in thePhysical layer) providing the scheduling assignment for the PUSCHtransmission, whether to perform concurrent transmission in a sub-frameof UCI in the PUCCH and data in the PUSCH. For example, if a UE is powerlimited, multiplexing UCI in the PUSCH may be preferable as any increasein the CM of the signal transmission due to concurrent PUCCH and PUSCHtransmissions will lead to power amplifier back-off and will be damagingto the reception reliability of both PUCCH and PUSCH transmissions.Moreover, the signal transmission in the PUCCH is interference limited,because several UEs multiplex UCI transmissions in the same BW as it waspreviously described for the HARQ-ACK and CQI transmission structures.Thus, the Node B may choose to configure some UEs to transmit UCI in thePUSCH as a mechanism for reducing PUCCH interference.

FIG. 9 is a diagram that illustrates the concept of enabling or notenabling concurrent PUCCH and PUSCH transmissions from a UE through theuse of an “Enable_PUCCH_PUSCH” flag consisting of 1 bit, according tothe first embodiment of the present invention. Upon the reception of the“Enable_PUCCH_PUSCH” flag from the Node B in step the UE examines itsvalue in step 920. If the value is zero then, when the UE has data andUCI transmission in the same sub-frame, it transmits UCI in the PUSCH instep 930. Otherwise, it transmits UCI in the PUCCH in step 940.

If the “Enable_PUCCH_PUSCH” flag is set through the DL control channelscheduling the PUSCH transmission then, depending on its value asdescribed in FIG. 9, the UE configures the potential UCI transmission inthe PUCCH or in the PUSCH and no further conditions are necessary.However, including one bit in the scheduling assignments for PUSCHtransmissions may often be wasteful, for example when the UE has no UCIto transmit, thereby leading to unnecessary control overhead. Settingthe “Enable_PUCCH_PUSCH” flag through higher layers (such as the MAC orthe RRC) is more efficient but cannot provide dynamic control for UCIinclusion in the PUSCH or its separate transmission in the PUCCH.

A second embodiment of the invention considers the conditions forenabling such dynamic control when the “Enable_PUCCH_PUSCH” flag is setthrough higher layers (MAC or RRC). When the “Enable_PUCCH_PUSCH” flagis 0, the UE always transmits UCI in the PUSCH when UCI and datatransmission occur in the same sub-frame. However, when the“Enable_PUCCH_PUSCH” flag is 1, this may provide a necessary butinsufficient condition for the UCI to be transmitted in the PUCCH whenthe same UE transmits data in the PUSCH in the same sub-frame. One ormore of the additional conditions that may need to be fulfilled aresubsequently described assuming that the “Enable_PUCCH_PUSCH” flag forthe reference UE is set to 1. This allows for, but does not mandate, UCItransmission in the PUCCH while the UE has data transmission in thePUSCH in the same sub-frame.

A first condition for transmitting UCI in the PUCCH while transmittingdata in the PUSCH in the same sub-frame is the amount of resourcesrequired for UCI transmission in the PUSCH which, based on previousdescription, can be proportional to the data MCS. Assuming Q′_(UCI)coded symbols are required for UCI in the PUSCH, as previously describedin case of HARQ-ACK, the UCI transmission occurs in the PUSCH if theratio of the UCI resources to the total resources available for datatransmission in the reference sub-frame, G_(UCI)=Q′_(UCI)/(M_(sc)^(PUSCH)·N_(symb) ^(PUSCH)), is smaller than or equal to a predeterminedthreshold T_(UCI), that is when G_(UCI)≦T_(UCI) where the UCI signal canbe any of the HARQ-ACK, RI, CQI, or PMI signals. Note that as the UCIresources are proportional to the data MCS in the PUSCH, the thresholdvalue may be interpreted as being an MCS value, which may further dependon the UCI type.

For multiple UCI signals, the corresponding ratios and thresholds can beadded or a new threshold may be defined. For example, if a UE needs totransmit both HARQ-ACK and CQI in a sub-frame where it also transmitsdata in the PUSCH, HARQ-ACK and CQI are transmitted in the PUSCH ifG_(HARQ-ACK)+G_(CQI)≦T_(HARQ-ACK)+T_(CQI). Alternatively, by introducinga new threshold, HARQ-ACK and CQI are transmitted in the PUSCH ifG_(HARQ-ACK)+G_(CQI)≦T_(HARQ-ACK) _(—) _(CQI) where T_(HARQ-ACK) _(—)_(CQI) is the threshold corresponding to both HARQ-ACK and CQItransmission in the PUSCH. This threshold may be different, preferablylarger, than T_(HARQ-ACK)+T_(CQI) since by transmitting both CQI andHARQ-ACK in the PUSCH, larger reduction in the PUCCH interference isachieved and a larger increase in the CM is avoided (in case ofconcurrent signal transmissions). The previous thresholds may havepredetermined values applicable to all UEs or they may be signaled tothe UEs through higher layer signaling.

FIG. 10 is a diagram illustrating the concept of using thresholds forthe ratio of UCI resources over the maximum resources available for datatransmission in the PUSCH during a reference sub-frame in order todecide whether the UCI transmission should occur in the PUSCH or thePUCCH, according to an embodiment of the present invention. The UE firstdetermines the UCI thresholds in step 1010, which are either included inthe system specifications or conveyed to the UE through higher layersignaling. Subsequently, the UE compares the ratio G_(UCI) of the totalUCI resources over the total resources available for data transmissionin the reference sub-frame to the respective UCI threshold T_(UCI) instep 1020. If G_(UCI)≦T_(UCI), the UE transmits UCI with data in thePUSCH in step 1030. Otherwise, the UE transmits UCI in the PUCCH in step1040.

A second condition for transmitting UCI in the PUCCH while transmittingdata in the PUSCH, in the same sub-frame, is the difference in therequired transmission power. A different transmission power controlscheme is assumed to apply for the PUCCH and the PUSCH. The transmissionpower in the PUCCH in the reference sub-frame based on the power controlmechanism applied to PUCCH transmissions is denoted by P_(PUCCH). Thetransmission power in the PUSCH in the reference sub-frame based on thepower control mechanism applied to PUSCH transmissions is denoted byP_(PSCCH). The invention considers that UCI can be transmitted in thePUCCH only if the difference in the two transmission powers is smallerthan or equal to a threshold T_(power), that is|P_(PUCCH)−P_(PUSCH)|≦T_(power). In a second realization, the squareroot of the PUCCH and PUSCH transmission powers may be considered andthen the criterion for UCI transmission in the PUCCH becomes |√{squareroot over (P_(PUCCH))}−√{square root over (P_(PUSCH))}|≦T′_(power).

The value for the threshold T_(power) (or T′_(power)) may be common toall UEs and either included in the specifications of the communicationsystem or signaled by the Node B through a broadcast channel. It mayalso be UE-specific and signaled by the Node B through higher layersignaling to the reference UE. Moreover, for concurrent PUCCH and PUSCHtransmissions, since the total UE transmission power needs to be keptbelow a maximum value P_(max) (for a given UE amplifier class), andsince the PUCCH is the more critical channel having lower BERrequirements and not benefiting from HARQ, the PUCCH transmission poweris kept at P_(PUCCH) and the PUSCH transmission power is eitherP_(max)−P_(PUCCH) if P_(max)−P_(PUCCH)≦P_(PUSCH), or it is P_(PUSCH) ifP_(max)−P_(PUCCH)>P_(PUSCH). It is noted that the Node B is typicallyaware of the change in the PUSCH transmission power and it canappropriately adjust the MCS of the data in the PUSCH to account forthat change.

FIG. 11 is a diagram that illustrates the concept of using thedifference between the transmission powers in a reference sub-frame ofthe individual PUCCH transmission (in the absence of PUSCH transmissionfrom a UE) and the individual PUSCH transmission (in the absence ofPUCCH transmission from the reference UE) to determine whether the UCIis transmitted in the PUCCH or in the PUSCH, according to an embodimentof the present invention. The UE first determines the difference|P_(PUCCH)−P_(PUSCH)| in step 1110 and subsequently compares it to thethreshold value T_(power) in step 1120. If|P_(PUCCH)−P_(PUSCH)|≦T_(power), the UE transmits UCI in the PUCCH instep 1130. Otherwise, the UE transmits UCI in the PUSCH in step 1140.

A third condition for transmitting UCI in the PUCCH, while transmittingdata in the PUSCH in the same sub-frame, is the number of differentPUCCH transmissions as identified by their corresponding frequency orcode (cyclic shift or orthogonal cover) resources. For example, a UE maybe receiving DL data packets independently in multiple ComponentCarriers (CCs) of a communication system. Multiple HARQ-ACKtransmissions are required, each corresponding to a codeword of the DLdata packet and each possibly requiring a separate respective frequencyor code resource. To avoid introducing PUCCH interference from multipleHARQ-ACK transmissions and avoid increasing the CM of the signaltransmission and the associated overhead from RS transmission, theHARQ-ACK transmission can be in the PUSCH. Therefore, the number ofseparate PUCCH resources required for UCI transmission can be anotherparameter in determining whether UCI transmission is in the PUCCH or inthe PUSCH.

If Q′_(ACK/NAK) coded symbols are required for HARQ-ACK transmissionassociated with one HARQ process and if Q″_(ACK/NAK) coded symbols arerequired for HARQ-ACK transmission associated with M HARQ processes, theHARQ-ACK transmission is in the PUSCH if {tilde over(G)}_(ACK/NAK)/(M_(sc) ^(PUSCH)·N_(symb) ^(PUSCH))≦w_(M)·T_(ACK/NAK),where w_(M) is a scaling factor with value depending on M, with w₁=1 forM=1 and w_(M-1)<w_(M) for M>1. For example, if Q″_(ACK/NAK), thenw_(M)>M in order to favorably bias HARQ-ACK transmission in the PUSCH incase multiple HARQ-ACK channels, as determined by frequency or coderesources, are required for HARQ-ACK transmission in the PUCCH. The samearguments can be extended in a straightforward manner for UCI signalsother than HARQ-ACK.

A fourth condition for transmitting UCI in the PUSCH, while transmittingdata in the PUSCH in the same sub-frame, is whether the PRBs of PUSCHtransmission are the same in both slots (localized transmission asopposed to transmission using frequency hopping). Localized PUSCHtransmission is typically the result of the Node B scheduler being ableto select PRBs where the signal transmission from the UE experiences ahigh SINR. Conversely, the PRBs where PUCCH transmission can occur aretypically predetermined and Frequency Hopping (FH) is applied for thetransmission in two slots to improve frequency diversity. Therefore, UCItransmission can occur in the PUSCH if the transmission of the latter islocalized (FH is not used), even though the potentially high SINR ofsuch PUSCH transmission is expected to be captured in the data MCS.Therefore, the fourth condition is already to some extent captured bythe first condition.

A fifth condition for transmitting UCI in the PUSCH, while transmittingdata in the PUSCH in the same sub-frame, is whether the datatransmission uses the MIMO principle for spatial multiplexing of datastreams in case the UE has multiple transmitter antennas. Because UCIand data multiplexing occurs prior to the DFT in FIG. 2, the UCItransmission will always experience interference regardless of the MIMOlayers used for UCI transmission. Since the UCI reception reliabilitywill then depend on the MIMO receiver used by the Node B for data andsince the UCI error requirements are typically significantly differentthan the data error requirements, the process of determining the UCIresources in the PUSCH in case MIMO as applied to the data transmissioncan become complex. To avoid such complexity and ensure the reliabilityof UCI reception regardless of the Node B receiver for MIMO, the UCItransmission may always be in the PUCCH when the data transmission inthe PUSCH uses spatial multiplexing, particularly since such a UE istypically not power limited. If the data transmission does not usespatial multiplexing of data streams (although it can use transmitterantenna diversity), the UE may transmit the UCI together with data inthe PUSCH, or it may examine additional conditions, as they werepreviously described, about whether the UCI transmission should betogether with data transmission in the PUSCH or, separate from datatransmission, in the PUCCH.

FIG. 12 is a diagram illustrating the concept of determining the channel(PUCCH or PUSCH) for UCI transmission based on whether or not MIMO forspatial multiplexing of data streams is applied to the data transmissionin the PUSCH, according to an embodiment of the present invention. If isdetermined that MIMO is applied to the data transmission in step 1210,UCI is transmitted in the PUCCH in step 1220; otherwise, UCI istransmitted in the PUSCH in step 1230.

Embodiments of the present invention now consider rules for deciding, inthe absence of PUSCH transmission in a reference sub-frame, whether tomultiplex UCI signals of different types in one PUCCH resource orwhether to use multiple PUCCH resources, one for each UCI signal. Anembodiment of the present invention considers the transmission in thesame sub-frame of two UCI signals where the first is an HARQ-ACK signaland the second is a CQI signal.

The HARQ-ACK and CQI transmission structures were described in FIG. 4and FIG. 5, respectively. Multiplexing HARQ-ACK and CQI transmissionscan be achieved by using the structure in FIG. 5 and scaling the secondRS (with “−1” for ACK and with “+1” for NAK) in each slot, as waspreviously described. Although this HARQ-ACK and CQI multiplexingtypically has negligible impact on the CQI BLER, it can lead tosubstantial degradation in the HARQ-ACK BER. As a consequence, UEsoperating in low SINRs may fail to meet the HARQ-ACK BER targets and itis then preferable for the HARQ-ACK to be transmitted using its ownPUCCH resources. This is despite the CM increase, which penalizes theHARQ-ACK and CQI reception reliability less that the HARQ-ACK and CQImultiplexing, especially for the HARQ-ACK.

Embodiments of the present invention assume that the Node B configures aUE through higher layer signaling (MAC or RRC) whether the HARQ-ACK andCQI transmissions are multiplexed, whenever they happen to occur in thesame sub-frame, in one PUCCH, or whether a separate PUCCH is used forthe transmission of each signal as when it occurs in the absence of theother. FIG. 13 is a diagram illustrating the concept of enabling or notenabling concurrent HARQ-ACK and CQI transmissions from a UE usingseparate channels in the PUCCH through the use of an“Enable_HARQ-ACK_CQI” flag, according to an embodiment of the presentinvention. This is analogous to the concurrent PUCCH and PUSCHtransmission described in FIG. 9. Upon the reception of the“Enable_HARQ-ACK_CQI” flag in step 1310, the UE examines its value instep 1320. If it is zero then, when the UE has HARQ-ACK and CQItransmission in the same sub-frame, it multiplexes the two signals instep 1330 using the CQI transmission structure. Otherwise, it transmitsHARQ-ACK and CQI using the individual PUCCH for each signal in step1340.

Another case requiring at least partially separate transmission ofHARQ-ACK and CQI signals in the PUCCH occurs when the UE hastransmission of more than 2 HARQ-ACK bits in a sub-frame. Embodiments ofthe present invention assume that HARQ-ACK from only a single HARQprocess for a maximum of 2 codewords is multiplexed in the CQItransmission structure of FIG. 5, as in 3GPP LTE. This is because of alimitation in the existing dimensions of the CQI transmission structurein which several HARQ-ACK bits are multiplexed without incurringsignificant performance losses. Therefore, a number of HARQ-ACK bitsequal to the number of CQI channels in the same sub-frame can bemultiplexed with the CQI signal transmission using the structure of FIG.5, while the remaining HARQ-ACK bits are transmitted using theirindividual PUCCH resources and the transmission structure of FIG. 4.This principle is illustrated in the diagram of FIG. 14, according to anembodiment of the present invention. In a reference sub-frame, 2HARQ-ACK bits are multiplexed with 1 CQI channel in step 1410 using thestructure of FIG. 5, as in 3GPP LTE. 1 HARQ-ACK channel is individuallytransmitted in step 1420 using the structure of FIG. 4.

Some of the conditions applied for the concurrent PUCCH and PUSCHtransmission can be extended to the case of multiple concurrent PUCCHtransmissions. For example, the second condition concerning the powerdifference among the concurrent transmissions may apply for multipleconcurrent PUCCH transmissions.

While the present invention has been shown and described with referenceto certain embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present invention asdefined by the appended claims.

What is claimed is:
 1. A method for transmitting control information bya terminal in a mobile communication system, the method comprising:identifying, by the terminal, information that indicates simultaneousshared channel and control channel transmission; transmitting, by theterminal, first control information on a control channel in a subframe;and transmitting, by the terminal, second control information on ashared channel in the subframe, wherein the first control informationcomprises at least one of an acknowledgement and a service request, andwherein the second control information comprises a channel qualityindicator (CQI).
 2. The method of claim 1, wherein the informationindicating simultaneous shared channel and control channel transmissionhas a binary value.
 3. The method of claim 2, wherein the informationcomprises a flag.
 4. The method of claim 1, wherein the informationindicating simultaneous shared channel and control channel transmissionis transmitted through a Radio Resource Control (RRC) layer.
 5. A methodfor transmitting control information by a terminal in a mobilecommunication system, the method comprising: determining, by theterminal, a ratio of an amount of resources required for transmission ofthe control information on a shared channel over a total amount ofresources available for transmission of data or the control informationon the shared channel; and transmitting, by the terminal, the controlinformation on the control channel and the data on the shared channel ina same subframe if the ratio is greater than a threshold value, whereinthe control information comprises at least one of an acknowledgement anda service request.
 6. The method of claim 5, wherein the threshold valueis at least one of predetermined and signaled to the terminal by a NodeB.
 7. A method for transmitting control information by a terminal in amobile communication system, the method comprising: transmitting thecontrol information on a control channel and data on a shared channel ina same subframe if a value of a modulation and coding scheme (MCS) usedfor the data is less than or equal to a predetermined MCS value, whereinthe control information comprises at least one of an acknowledgement anda service request.
 8. A terminal apparatus for transmitting controlinformation in a mobile communication system, the apparatus comprising:a transceiver for transmitting and receiving a signal; and a controllerfor comparing a ratio of an amount of resources required fortransmission of control information on a shared channel over a totalamount of resources available for transmission of data or the controlinformation on the shared channel to a threshold value, and fortransmitting the control information on a control channel and the dataon the shared channel in a same subframe if the ratio is greater thanthe threshold value, wherein the control information comprises at leastone of an acknowledgement (ACK) and a service request (SR).
 9. Theapparatus of claim 8, wherein the threshold value depends on an amountof control information.
 10. The apparatus of claim 9, wherein the amountof control information is a number of ACK bits, or a number of the ACKbits and channel quality indicator (CQI) bits.
 11. A terminal apparatusfor transmitting control information and data in a mobile communicationsystem, the apparatus comprising: a transceiver for transmitting andreceiving a signal; and a controller operating for transmitting controlinformation on a control channel and data on a shared channel in a samesubframe if a value of a modulation and coding scheme (MCS) used fordata transmission is less than or equal to a predetermined MCS value,wherein the control information comprises at least one of anacknowledgement and a service request (SR).
 12. The apparatus of claim11, wherein the predetermined MCS value is dependent on a type of thecontrol information.
 13. The apparatus of claim 11, wherein thepredetermined MCS value is signaled to the terminal by a Node B.
 14. Aterminal apparatus for transmitting control information in a mobilecommunication system, the apparatus comprising: a transceiver fortransmitting and receiving a signal; and a controller for identifyinginformation that indicates simultaneous shared channel and controlchannel transmission, for transmitting first control information on acontrol channel in a subframe, and for transmitting second controlinformation on a shared channel in the subframe, wherein the firstcontrol information comprises at least one of an acknowledgement (ACK)and a service request (SR), and wherein the second control informationcomprises a channel quality indicator (CQI).
 15. The apparatus of claim14, wherein the information indicating simultaneous shared channel andcontrol channel transmission has a binary value.
 16. The apparatus ofclaim 14, wherein the information indicating simultaneous shared channeland control channel transmission is transmitted through a radio resourcecontrol (RRC) layer.